OBLIQUE (ANTERIOR TO PSOAS) CAGE TECHNIQUES FOR DEFORMITY G. - - PDF document

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OBLIQUE (ANTERIOR TO PSOAS) CAGE TECHNIQUES FOR DEFORMITY

• G. Swamy, MD FRCSC

University of Calgary Spine Program

DISCLOSURES

Honorarium Recipient- Stryker

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Oblique Interbody Fusions

• Define: Anterior

retroperitoneal lumbar discectomy and cage insertion

• Exploits plane to left of

aorta, and anterior to psoas (ATP)

• Main rationale – avoid

trans-psoas dissection

Oblique Cage Techniques for Deformity

• Lateral cages are helpful

in adult deformity

• Does the oblique cage
• ffer substantive

differences between LLIF?

• Examine
• Oblique fusions mobile

lumbar spine

• Oblique approach to L5-S1

Agenda

• Brief history of anterior

retroperitoneal surgery

• Rationale for anterior
• blique work in adult

spinal deformity

• Technical points
• Complications
• Cases

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Anterior Spinal Surgery

1956 CORR

• Credits lumbar retroperitoneal approaches

to kidney approaches (Digby 1941) 1934 JBJS

Anterior Spinal Surgery

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Adult Spinal Deformity Surgery 1970s

1973 CORR 1975 JBJS 1981 JBJS

Adult Deformity Surgery 1980s/1990s

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Adult Deformity Surgery – Posterior Only

Stage I

• LLIFs L1-2, 2-3, 3-4, 4-5
• L3-4 and up: chest wall

impedes access

• Osteotomize ribs in line

with spine

• Diaphragm perforated

(and sewn) for tube

• Chest tube postop X 36

hrs Stage II

• L5-S1 TLIF, T11-Ilium
• Hybrid open TL, MIS L2-

S1

• V. small concave apical

pedicles - left

• Coronal plane bend built

back in for balance

MIS Deformity

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1.

Dealing with high iliac crest and ‘deep-seated’ L4-5

2.

Hip pain or cruralgia

3.

Nerve injuries

4.

Inadequate lordosis

• Place cages anteriorly
• Need for ACR

5.

Inability to access L5-S1 from lateral approach

Technical problems with LLIF in deformity

Deep-seated L4-5

Very painful – far out of the

• rdinary

Did 2. Never again.

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Iliac crest osteotomy Deep-seated L4-5

Answers

• Angled implants (can’t see disc preparation directly)
• Iliac osteotomy (pain)
• Oblique approach

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Deep-seated L4-5

R.A. Hynes From Chapter 34, Surgical Approaches to the Spine, 3rd Ed, Springer 2015

Cage goes in obliquely, but can be manoevered to lie transversely

Hip Pain after LLIF

• Femoral nerve
• Obturator nerve injuries
• LFCN injuries
• Genitofemoral nerve injuries
• Cummock et al JNS 2013
• 64% postoperative symptoms
• By 3 months, more than ½ of these resolve
• By 1 year, 90% resolve
• Lee et al Spine J 2013
• Hip flexion strength decreased for first 2 / 52 postop
• No differences afterwards

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Hip pain after LLIF

• Can be a great source of discomfort
• In our experience, large psoas (young men and women)

means more postoperative thigh discomfort

• Avoiding going through psoas altogether may be useful

Nerve injury and LLIF

• In over 600 cages, we have had no permanent motor

palsies – MEPs and SSEPs used

• Have had 3 late quads palsies (after 2nd stage instrumentation) – in

conjunction with SPO in 2 cases

• 4 or 5 L4-5 levels abandoned – no reasonable place to

dock

• (Importance of blunt finger dissection through psoas)
• Lykissas 2013 (n=453 patients, 919 levels)
• 9.6% permanent sensory deficits
• 2.3% permanent motor deficits

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How do nerve injuries occur?

• Uribe 2015
• Retraction time at L4-5
• Coincident increase in t-EMG threshold
• Bendersky 2015 – rigorous

electrode positioning, including upper lumbar roots

• Answer if alert: Move retractor anteriorly

How do nerve injuries occur?

Davis TT – JSDT 2015

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How do nerve injuries occur?

Retraction of blades on femoral nerve Staying anterior to psoas avoids the problem.

Inadequate Lordosis

• Can LLIF restore lordosis?

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Inadequate lordosis

• Literature is mixed
• Sembrano 2014
• Acosta 2011
• Kepler 2012
• Anterior cage placement best
• Kepler 2012
• Sridharan (submitted for publication)

Inadequate Lordosis - ACR

From Akbarnia et al 2013

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Potential complications – oblique approaches

• Sympathetic injury
• Vessel injury
• Iliolumbar vein
• Inadvertant anterior annulus and ALL resection
• Dural tear

Case – Painful Adult Idiopathic Scoliosis

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Case – Painful Adult Idiopathic Scoliosis

3 mg rhBMP2 / level Percutaneous posterior lumbar Open thoracic Complications: Ileus Edema Transaminitis (hx of EtOH) Doing well

Case – Rapidly progressive deformity after intrathecal narcotic pump / syrinx

Symptoms Intractable LBP R leg pain Not flexible PMHx Syrinx Chiari Narcotic pain pump

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Case – Rapidly progressive deformity after intrathecal narcotic pump / syrinx

Anterior stage uncomplicated x hours y EBL Posterior stage missing 10 deg required PSO x hours y EBL z complications Pt doing well

Case – Previous fusion, now painful TL curve with distal degeneration

Fused to L2 L4-5 very oblique and deep First stage OLIF L L4-5 and L5-S1 LLIF R L2-3 and 3-4

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Case – Previous fusion, now painful TL curve with distal degeneration